Do You Saponify?
Do you saponify? Some of my best friends do. And although it can be quite dangerous without proper precautions and can be addicting, it is still good clean fun. I am proud to be a professional soapmaker and keep company with other soapmakers; they are among the nicest people I know!
Saponification is the base promoted hydroysis of an ester to produce an alcohol and the sodium salt of that acid. What?? OK, lets break it down. The ester used in soapmaking is a triglyceride, also called a triacylglyerol. This is a type of fat consisting of a glycerol (3 carbon sugar) which is attached to 3 fatty acids through a ester bond. The fatty acids in the picture are the 3 tails sticking out to the left and the glycerol is the 3 carbon backbone running vertically on the right. There are many different types of fatty acids and the three fatty acids found in any triglyceride will vary. The ester bonds are between the O (oxygen) on the glycerol and the C=O on the fatty acid.
When soap is made this bond between the fatty acids and glycerol is broken by the presence of a strong base or alkali, this means something with a very high pH. This strong base is sodium hydroxide (NaOH). Yes, it is drain cleaner and a very dangerous substance when not handled properly. We soapmakers take proper precautions. And just to make sure you keep reading, I will tell you now that finished soap is completely safe because there is no lye left in the soap when done properly. We know alot today about this chemical reaction and can actually calculate the precise amount of lye necessary to react with various oils. Soapmakers generally use online calculators to determine the exact amount of lye to use in their individual recipe and then add little bit more oil to ‘superfat’ the soap making it more mild. Previous generations did not have this so many of ‘Grandma’s’ soaps came out heavy on the lye and were quite harsh. Today handcrafted soaps are very mild and the soapmaker can vary characteristics of the soap by using different triglycerides or oils.
OK, back to the saponification reaction. The NaOH breaks the ester bond between the glycerol and fatty acids. The -OH (hydroxide) part of the NaOH chemically or covalently binds to the glycerol side while the Na (sodium) chemically binds to the fatty acids. Now instead of a triglyceride we have a free glycerol molecule and a sodium (Na) salt of the fatty acid. Wow! Chemistry in action. Small soapmakers will leave the glycerol (also called glycerin) in the soap and it makes a great moisturizer. Some large companies will remove the glycerin to use for other purposes. If you’ve never tried a bar of handcrafted soap, you don’t know what you are missing. These are generally very mild and moisturizing cleansers compared to grocery store big brands, most of which are technically not soap.
Everybody makes soaps a little differently. Some people go for the latest bath and body scents, others go for the visual effect and make beautiful works of art from their soap. Being an herbalist, I am always looking for herbs that can benefit a bar of soap. Some of my favorites for soap include calendula, mint, lavender, rosemary.
While soapmaking has been around for sometime it recently has boomed as a cottage industry and soapmakers even have their own professional organization; the Handcrafted Soapmakers Guild. If you are interested in soapmaking visit there to find out more. What is your favorite kind of soap?
More about the author: Cindy Jones is a formulator and microbiologist. After receiving a Ph.D. in biochemistry from the University of Cincinnati she worked in cancer research, later as a health/medical writer and now in cosmetic science. Read more from this author